Self-sealing gasket for pipe joints



ot.4,1966' J. T.DUN'TON v3,276,792

SELFSEALING GASKET FOR PIPE JOINTS .NNW

1F7- f i Il? d INVENTOR.

Oct; 4, 1966 J. T. DUNToN 3,276,792

SELF-SEALING GASKET FOR PIPE JOITS Original Filed July 9. 1962 2Sheets-Sheet 2 Armen/5K United States Patent Gftice Patented Oct. 4,1966 3,276,792 SELF-SEALING GASKET FoR PIPE JolNTs John T. Dunton,Bradford, Pa., assignor to Dresser Indus- This application is acontinuation of my copending application Serial No. 208,322, tiled July9, 1962 and now abandoned.

The present invention relates to those gaskets which are included as anelement of a pipe joint and is concerned primarily with a gasket of theso-called self sealing type.

The objects and advantages of the present invention will be explained inconjunction with one type of coupling for light wall pipe. However, itis to be lclearly understood that neither the coupling nor the pipe area limitation on the invention.

In a pipe coupling including a self sealing gasket of the type withwhich this invention `is concerned, pressure of the line content forcesthe gasket into sealing engagement with the bore of the pipe. However,if this pressure is to be effective in the manner intended it is of theutmost importance that none of the line content get in behind thegasket. That is, there should be no line content between the gasket andthe bore of the pipe. If this should occur, the pressure of the linecontent will be neutralized and the sealing effect lost.

Because of this it has been recognized that an initial seal between thegasket and the pipe bore is of importance. However, the initial sealsheretofore provided have been in the natural of a Iline contact whichpresents a strong possibility that this initial seal wil be imparied.Moreover, any gaskets which have provided for a surface contact with thepipe bore have done so only with a pressure that has proven to beinadequate.

With the foregoing conditions in mind, the present invention has in viewas its foremost objective the provision, in a pipe coupling, of a selfsealing [gasket which includes means which denitely assures of aninitial seal that is characterized by an area Contact over anappreciable cylindrical surface and under substantial and adequatepressure. This initial seal is established as the pipe joint isassembled and is entirely independent of the pressure of the :linecontent. It is later emphasized and strengthened by the pressure of theline content.

One type of pipe joint which utilizes a self sealing gasket is such asthat illustrated in the co-pending application of Frederick T. Newell etal., Serial #94,831, filed March 10, 1961, now abandoned, for Couplingfor Light Wall Pipe, and reled as a continuation-inpart on September 9,1964, Serial No. 396,474, 110W abandoned. In a pipe joint of this type agasket is em ployed and this gasket includes a central rib or flangewhich is interposed between the meeting pipe ends. Extending axiallyoutwardly from the opposite sides of this flange are two flaredextensions each of which ts into one of the meeting pipe ends. Prior toassembly each of these extensions has a maximum outside diameter that isgreater than the bore of the pipe into which it is to be inserted. Thus,the insertion entails the compression of the ared extension whichresults in the initial seal above mentioned. However, in the joint ofthe above identified co-pending application and in other known jointsthere is nothing to hold the central portion of the gasket againstradial collapse or compression with the ultimate result that the initialseal is a line contact rather than an area contact, and even if somemeasure of a surface contact, is obtained, the radial outward pressuregenerated by the gasket is inadequate to achieve the initial sealrequired.

With these conditions in mind, a further highly important object of theinvention is to provide a self sealing gasket of the character aforesaidwhich includes a central portion having an external rib or ange that isintended to be inserted between meeting .pipe ends together withmechanical means for maintaining this central portion at a predetermineddiameter against the influence of a compression of the ared extensions.This results in the generation of an outward radial pressure byextensions as they are compressed for pipe insertion purposes and thispressure has no component directed -away from the -meeting ends. Anycomponent, other than radial, which is generated, will be towards themeeting ends.

More in detail the invention has as an object, the provision of a selfsealing gasket of the character indicated in which the central flange isof rubber or a comparable elastomer material land is integrally joinedto the ared extensions. Mechanically bonded and interlocking with thiscentral ange is a metallic ring. This ring serves to maintain thatportion of the gasket immediately continguous to the ange to thediameter of the pipe bore. Thus, as the flared extensions are compressedand contracted as they are inserted into the pipe bore, the centralportion of the gasket does not collapse and in effect, provides anadditional compressive force on those portions of the gasket in contactwith the pipe bore. This surface contact provides the initial seal underhigh pressure which is of such importance in a self sealing gasket ofthis type.

Still more in detail the invention has as -an object, the provision of aself sealing gasket of the type indicated in which a metallic ring isformed with a series of apertures and is molded or vulcanized into thecentral ange. As this is done, the rubber material of the flange passesthrough the apertures and establishes the mechanical bond or interlockabove mentioned.

Still another object in view is to provide a self sealing gasket of thecharacter aforesaid in which each end of each flared extension is formedas an inwardly tapering conical surface. This surface facilitatesinsertion into the bore of the pipe.

Vairous other more detailed objects and advantages of Ithe inventionsuch as arise in connection with carrying out the above noted ideas in apractical embodiment will in part become apparent and in part behereinafter stated as a description of the invention proceeds.V

The invention therefore comprises a self sealing gasket for a pipe jointwhich is characterized as including a central portion having an externalange with a metallic ring associated therewith for maintaining thiscentral portion a predetermined diameter which is the bore of the pipeinto Iwhich the flared extensions of the gasket are to be insertedwhereby maximum outward radial pressure is created in these extensions.

For a full and more complete understanding of the invention, referencemay be had to the following description and accompanying drawings,wherein:

FIGURE 1 is a view of a pipe coupling including the self sealing gasketof this invention. In this view a portion of the coupling and pipetogether with the gasket are broken away and shown in sections.

FIGURE 2 is a view taken on an enlarged scale of the gasket per se withparts broken away and shown in section.

FIGURE 3 is a detailed section through a portion of 3 the gasket beingtaken about on the plane represented by the line 3-3 of FIGURE 2.

FIGURE 4 is another detailed section taken about on the planerepresented by the line 4 4 of FIGURE 3.

FIGURE 5 is still another detailed section taken about on the planerepresented .by the line 5-5 of FIGURE 3.

FIGURE 6 is an elevation of the reinforcing ring per se; and

FIGURE 7 is a side view of the ring of FIGURE 6 being taken on theplanes normal thereto as represented by the line 7-7 of FIGURE 6.

Referring now to the drawings and first more particularly to FIGURE1,'one type of the pipe joint -with which the self sealing gasket ofthis invention may be utilized is therein illustrated. As mentionedabove, however, this particular type of joint is not to be considered alimitation on the invention because the gasket will find utility inother joints.

FIGURE 1 shows two pipes ends P and P which in the present instance arelight wall pipe. The bores of the pipe P and P are coated with a plasticlining 10. Each of the pipes P and P is enlarged adjacent its free endto provide shoulders at 11 and 12. A sleeve 13 is fitted over the pipe Pand has a conical shoulder 14 which engages the shoulder 11. This sleeve13 is exteriorly threaded as indicated at 15.

A coupling member 16 is interiorly threaded as indicated at 17 and thesethreads mesh with the threads 15. The coupling member 16 has an internalshoulder at 18 which engages the shoulder 12 on the pipe P'. Obviously,the coupling members 13 and 16 may be relatively rotated and due to thethreaded connections 15 and 17 will be drawn together. It is furthernoted that the pipe P has an end face at 19 and the pipe P' an end faceat 20. I

A gasket which is referred to in its entirety by the reference characterG is included in the manner now to be described and this gasket is ofthe self sealing type.

Referring now more particularly to FIGURES 2 to 5 inclusive, it is firstnoted that the gasket G is of rubber or a comparable elastomer materialwhich is susceptible of being molded or vulcanized. The gasket Gincludes a central rib or flange 22 and when in a free or unconfinedcondition there is a cylindrical surface at 23 opposite the ange 22.Between this flange 22 and surface 23 there is a portion 24 which isidentified as the central portion of the gasket. Integrally .joined tothis central portion 24 and extending axially outwardly therefrom at oneside, is a flared extension 25 defined by an outer frusto-conicalsurface 26 and an inner conical surface 27. This flared extension 25terminates in a lip defined by conical surfaces 28 and 29.

At the other side of the central portion 24 `and integrally joinedthereto is a second flared extension 30 having the same structuralcharacteristics as those described in connection with extension 25.

A metallic lreinforcing ring is shown in detail in FIG- URES 6 and 7 andreferred to in its entirety by the reference character R and is made ofany appropriate metal having the required properties of strength andrigidity and is formed with a series of apertures 31. This ring R isembedded in the central ange 22 .in the manner depicted in FIGURES 2 to5 inclusive. When so embedded the rubber of the gasket occupies theaperture 31 and provides a good mechanical interlock or bond between thering R and the tiange 22 of the gasket. Obviously, this structuralarrangement may be readily achieved by establishing the interlock as thegasket G ist'vulcanized or molded.

Operation While the manner in which the self sealing gasket'of thisinvention functions is believed to be obvious from the illustration onthe drawings and description of the parts given, it may be brieflyoutlined as follows:

The gasket G is dimensioned with respect to the pipes P and P so thatabout 6% compression will be required to insert the extensions 25 and 30into the pipe P and P respectively. The Vdiameter of the cylindricalsurface 23 will be substantially the same that it is intended yto havein the assembled joint.

As the extensions 25 and 30 are compressed to achieve their insertioninto the pipe ends, the reinforcing ring R holds and maintains thediameter of the central portion 24 of the gasket. Thus, there is nocollapse or compression of the central portion. At the same time,additional compressive force is applied to those portions of theextensions which engage the bore of the pipe. After insertion has beenaccomplished, the surface at 26 on the extensions which were conical inthe free condition of the gasket, are transformed into substantiallycylindrical surfaces which engage with cylindrical bores of the pipeends. This engagement takes place with greater compressive force at thezones adjacent to the ends of the extensions. Thus, there is surfacecontact which provides a good initial seal. With this surface contactobtaining it is utterly impossible for any of the line content to get inback of the gasket where it would neutralize the pressure of the linecontent. At the same time, the rubber on the exposed bores of the rib 22by engaging the pipe ends 19 and 20 provides a supplemental seal whichis particularly important should there be a tendency for a vacuumcondition to be created.

After the joint in assembled and the pressure of the line contentbecomes effective, the additional pressure forces the extensions 25 and30 into even better sealing engagement with the bore of the pipe.

While a preferred specific embodiment of the invention is hereinbeforeset forth, it is to be clearly understood that the invention is not tobe limited to the exact constructions, materials, or devices illustratedand described because various modifications of these details may beproivided in putting the invention into practice within the purview ofthe appended claims.

What is claimed is:

1. A pipe joint assembly, comprising a pair of aligned cylindrical pipeends having their edges in confronting relation and an annularelastomeric gasket ring having integral extensions projecting axiallyinto engagement with the internal surfaces of both pipe bores, saidextensions having substantially parallel frustro-conical inner and outersurfaces'diverging radially outwardly from a central portion when in theunstressed, unconfined condition, each of said outer surfaces having anoutside` diameter at said central portion which is substantially thesame as the inside diameter of the pipe bore and an outside diameter atits outer end which is considerably greater than said insidediameter ofthe pipe bore, whereby the inherent resilience .of the gasket isinitially intended to deform and press said outer surfaces into completesealing contact with the pipe bores, and a integral iiange projectingoutwardly from said central portion and disposed between saidconfronting edges of the pipe ends, the radially inward section of thegasket having an axial length at least as great as said flange, theradial and axial lengths of said flange and said Vsection defining azone, and a substantially non-deformable rigid ring structurally securedto said gasket within said zone, said ring being so dimensioned andlocated in said zone to positively maintain the diameter of the gasketfixed against inherent forces tending to collapse the central portion,the average` cross-sectional thickness of said extensions for asubstantial portion of their length and the cross-sectional thickness ofsaid central portion ofthe gasket. all being substantially the same,thereby to insure the initial fiat sealing contact of said outersurfaces within the pipe bores.

2. A pipe joint assembly according to claim 1, wherein said ring kisembedded within the elastomeric material forming the gasket.

3. A pipe joint assembly according to claim 1, wherein said ring isembedded Within said ange.

References Cited by the Examiner UNITED STATES PATENTS 10/ 1934Haushalter 285-110 X 7/1946 Hertzell v 285-370 X 6 FOREIGN PATENTS

1. A PIPE JOINT ASSEMBLY, COMPRISING A PAIR OF ALIGNED CYLINDRICAL PIPEENDS HAVING THEIR EDGES IN CONFRONTING RELATION AND AN ANNULARELASTOMERIC GASKET RING HAVING INTEGRAL EXTENSIONS PROJECTING AXIALLYINTO ENGAGEMENT WITH THE INTERNAL SURFACES OF BOTH PIPE BORES, SAIDEXTENSIONS HAVING SUBSTANTIALLY PARALLEL FRUSTRO-CONICAL INNER AND OUTERSURFACES DIVERGING RADIALLY OUTWARDLY FROM A CENTRAL PORTION WHEN IN THEUNSTRESSED, UNCONFINED CONDITION, EACH OF SAID OUTER SURFACES HAVING ANOUTSIDE DIAMETER AT SAID CENTRAL PORTION WHICH IS SUBSTANTIALLY THE SAMEAS THE INSIDE DIAMETER OF THE PIPE BORE AND AN OUTSIDE DIAMETER AT ITSOUTER END WHICH IS CONSIDERABLY GREATER THAN SAID INSIDE DIAMETER OF THEPIPE BORE, WHEREBY THE INHERENT RESILIENCE OF THE GASKET IS INITIALLYINTENDED TO DEFORM AND PRESS SAID OUTER SURFACES INTO COMPLETE SEALINGCONTACT WITH THE PIPE BORES, AND A INTEGRAL FLANGE PROJECTING OUTWARDLYFORM SAID CENTRAL PORTION AN DISPOSED BETWEEN SAID CONFRONTING EDGES OFTHE PIPE ENDS, THE RADIALLY INSAID SECTION OF THE GASKET HAVING AN AXIALLENGTH AT LEAST AS GREAT AS SAID FLANGE, THE RADIAL AND AXIAL LENGTHS OFSAID FLANGE AND SAID SECTION DEFINING A ZONE, AND A